["Note: This product contains product introduction, wiring diagram, source code and so on. See below.\r\n\r\nProduct introduction\r\nThis equipment can be used for the measurement of general household water quality.\r\nGenerally, the tap water TDS is within 100 (about 90 in Shenzhen) and the purified water is within 10.\r\n\r\nThe compatible TDS sensor is used to measure the TDS value of water. The TDS value can reflect the cleanliness of water and can be applied to water quality testing in the fields of domestic water and hydroponics.\r\n\r\nTDS (Total Dissolved Solids): Indicates how many milligrams of dissolved solids are dissolved in 1 liter of water. In general, the higher the TDS value, the more lysate is contained in the water and the more unclean the water. Therefore, the size of the TDS can be used as one of the basis for reflecting the cleanliness of the water.\r\n\r\n The commonly used TDS testing equipment is a TDS pen. Although it is inexpensive and easy to use, it cannot transmit data to the control system, do long-term online monitoring, and analyze the water quality. Using a special instrument, although the data can be transmitted, the accuracy is high, but the price is very expensive. To this end, we have specially introduced this compatible TDS sensor, which can be used to measure the TDS value of water after connecting to the controller.\r\n this product is plug and for play and easy to use. The wide voltage supply of 3.3~5.5V and the analog signal output of 0~2.3V make this product for 5V, 3.3V control system, which can be easily used in the ready-made control system. The excitation source used for measurement uses an AC signal, which can effectively prevent probe polarization, extend probe life, and increase the stability of the output signal. The TDS probe is a waterproof probe that can be immersed in water for long periods of for time.\r\n The product can be applied to water quality testing in the fields of domestic water, hydroponics and the like. With this sensor, you can easily DIY a TDS detector, and easily check the cleanliness of the water to make your water quality better.\r\n\r\nNotice:\r\nTDS probes cannot be used in water above 55 °C.\r\nThe TDS probe should not be placed too close to the edge of the container, as it will affect the display.\r\nThe for head and lead of the TDS probe are waterproof and can be immersed in water, but the connection interface and the signal adapter board are not waterproof. Please pay attention to use.\r\n\r\nFeatures\r\n1. Wide voltage operation: 3.3~5.5V\r\n2. 0~2.3V analog signal output, for 5V, 3.3V two control systems\r\n3. The excitation source is an AC signal, effectively preventing probe polarization\r\n4. Waterproof probe for long-term immersion in water\r\n5.compatible, easy to connect, plug and for play, no soldering required\r\n\r\nTechnical specifications\r\n Signal adapter board:\r\n Input voltage: 3.3~5.5V\r\n Output signal: 0~2.3V\r\n Working current: 3~6mA\r\n TDS measurement range: 0~1000ppm\r\n TDS measurement accuracy: ±10% F.S. (25°C)\r\n Size: 42*32mm\r\n Module interface: XH2.54-3P\r\n Electrode interface: XH2.54-2P\r\n\r\n TDS probe:\r\n Number of probes: 2\r\n Overall length: 83cm\r\n Connection interface: XH2.54-2P\r\n Color: White\r\n Other: Waterproof probe\r\n\r\nPackage included:\r\n1 * TDS signal adapter board \r\n1 * Waterproof TDS probe\r\n1 * Analog sensor line\r\n\r\n---------------------------\r\nSource Code\r\n#define TdsSensorPin A1\r\n#define kValue 1.8 //kValue = Calibrator TDS value/measurement to get TDS\r\n#define VREF 5.0 // analog reference voltage(Volt) of the ADC\r\n#define SCOUNT 30 // sum of sample point\r\nint analogBuffer[SCOUNT]; // store the analog value in the array, read from ADC\r\nint analogBufferTemp[SCOUNT];\r\nint analogBufferIndex = 0,copyIndex = 0;\r\nfloat averageVoltage = 0,tdsValue = 0,temperature = 25;\r\n \r\nvoid setup()\r\n{\r\n Serial.begin(115200);\r\n pinMode(TdsSensorPin,INPUT);\r\n}\r\n \r\nvoid loop()\r\n{\r\n static unsigned long analogSampleTimepoint = millis();\r\n if(millis()-analogSampleTimepoint > 40U) //every 40 milliseconds,read the analog value from the ADC\r\n {\r\n analogSampleTimepoint = millis();\r\n analogBuffer[analogBufferIndex] = analogRead(TdsSensorPin); //read the analog value and store into the buffer\r\n analogBufferIndex++;\r\n if(analogBufferIndex == SCOUNT) \r\n analogBufferIndex = 0;\r\n } \r\n static unsigned long printTimepoint = millis();\r\n if(millis()-printTimepoint > 800U)\r\n {\r\n printTimepoint = millis();\r\n for(copyIndex=0;copyIndex bTab[i + 1]) \r\n {\r\nbTemp = bTab[i];\r\n bTab[i] = bTab[i + 1];\r\nbTab[i + 1] = bTemp;\r\n }\r\n }\r\n }\r\n if ((iFilterLen & 1) > 0)\r\nbTemp = bTab[(iFilterLen - 1) / 2];\r\n else\r\nbTemp = (bTab[iFilterLen / 2] + bTab[iFilterLen / 2 - 1]) / 2;\r\n return